Variable-ratio belt-type transmission for engine-driven cycle, incorporating pedal-operated engine starting means

ABSTRACT

An engine-driven cycle having a variable-ratio belt-type transmission incorporating pedal-operated means for starting the engine. The transmission transmits power from a driving shaft of the engine to a driven shaft of the cycle when the engine is running, and transmits pedal-generated power from the driven shaft to the driving shaft to start the engine when it is not running.

Wnitefl States Patent 11 1 Svenson 1 Sept. 11, 1973 [54] VARIABLE-RATIOBELT-TYPE 2,678,117 5/1954 Birbaum 74/810 TRANSMISSION FOR ENGINE DRIVEN1,180,697 4/1916 Cobb 74/810 CYCLE, INCORPORATING 3:23:33 2323EZ'QQ'TiTIII 7i, ?3 PEDALOPERATED ENGINE STARTING 2,986,043 5/1961Jaulmes.... 74 230.17 E MEANS 3,362,242 1/1968 Watkins 74/230.17 E [75Inventor: Bert N. Svenson, Norwalk, Calif.

[73] Assignee: Instrument Systems Corporation, Primary Examiner-C HusarJericho, Att0rneyRobert L. Parker et al7 [22] Filed: June 7, 1971 [21]Appl. No; 150,523 [57] ABSTRACT An engine-driven cycle having avariable-ratio belt- [52] 74/2301; 74/810 type transmissionincorporating pedal-operated means 51 I l 192/4892 for starting theengine. The transmission transmits FI-lt. C power from a driving shaftof the engine to a driven of Search 74/230'17 shaft of the cycle whenthe engine is running, and trans- 74/810 23017 192/4892 mitspedal-generated power from the driven shaft to e ence C edtiiiiegelriving shaft to start the engine when it is not run- UNITEDSTATES PATENTS 2,678,566 5/1954 Oehrli 74/230.17 E 13 Claims, 8 DrawingFigures Pahznied Sept. 11, 1973 3 Sheets-Sheet 5 mus/woe BERT M Sum/501v5y H/S ATTORNEYS #42/2/5, Mac/4 P055521- A seu BACKGROUND OF INVENTIONThe present invention relates in general to a variableratio belt-typetransmission for transmitting power from a driving shaft of an engine toa driven shaft when the engine is running and for transmitting powerfrom the driven shaft to the driving shaft to start the engine when itis not running. The invention is particularly ap-' plicable to, and, forconvenience, will be considered in connection with, a pedal-equippedengine-driven cycle wherein pedal-generated power is delivered to thedriving shaft for engine starting purposes. 1

As further background, the variable-ratio belt-type transmission of theinvention includes: a variable-pitchdiameter driving pulley on thedriving or engine shaft and comprising two coaxial, relatively axiallymovable, generally frusto-conical driving pulley members; avariable-pitch-diameter driven pulley on the driven shaft and comprisingtwo coaxial, relatively axially movable, generally frustoconical drivenpulley members; a V-belt trained around the driving" and driven pulleys;overrunning clutch means on the driving shaft between the driving pulleymembers and engageable by the inner periphery of the belt; theclutch-means being engaged when the driven pulley drives the belt,whereby the engine may be started by means of pedal generated powerapplied to the driven shaft and delivered to the driving or engine shaftthrough the driven pulley, the belt and the clutch means; the clutchmeans being disengaged when the engine is running, whereby power may betransmitted from the driving shaft to the driven shaft through thedriving pulley,.thebelt'and the driven pulley; and driving-pulleyclosing means opera ble when the clutch means is disengaged, andresponsive to the speed of rotation of the driving shaft, for relativelymoving the driving pulley members axially toward each other to increasethe pitch diameter of the driving pulley, the pitch diameter of thedriven decreasing correspondingly. p

With the foregoing construction, the engine with which the cycle isequipped maybe started initially by pedaling, the pedal-generated powerbeing transmitted to the engine by automatic engagement of the overrunning clutch means in response to power application to the drivenshaft.'As soon-as the engine starts, the overrunning clutch meansdisengagesand'power is transmitted from the driving pulley to the drivenpulley through the belt in the normal manner for a transmission of thistype. The speed-responsive driving-pulley closing means causes thetransmission ratio to shift up" as the engine speedincreases.

SUMMARY AND OBJECTS OF INVENTION pulley The primary object of theinvention is to provide a variable-ratio belt-type transmission havingthe foregoing characteristics wherein the driving pulley is providedwith a driving-pulley closing means operable when the overrunning clutchmeans is engaged during starting of the engine. With this construction,the driving pulley is closed on the belt during starting for efficienttransmission of pedal-generated power to the engine.

An object related to the foregoing is to provide a driving-pulleyclosing means, operable during starting .line 8--8 of FIG. 7.

of the engine, which includes: circumferentially extending grooves ofcircumferentially decreasing depth in one of the driving pulley members;balls in the respective grooves; and means for displacing the ballstoward the shallower ends of the grooves to close the driving pulley onthe belt.

Another object of the invention is to provide a driving pulley whereinthe same balls used to close the driving pulley during starting of theengine are also used to close the driving pulley to shift thetransmission ratio up in response to increasing engine speed afterstarting of the engine, the balls under such conditions being disposedin radial grooves of radially-outwardly decreasing depth. H I Thus, inaccordance with the present invention, the same balls are used to closethe driving pulley both during starting of the engine and "when theengine is running, which is an important feature. 7

Another important object of the invention is to provide a variable-ratiobelt-type transmission of the fore-' going nature including torqueresponsive means for axially separating the driven pulley members todecrease the pitch diameter of the driven pulley in response .to

DESCRIPTION O DRAWINGS In the drawings: FIG. 1 illustrates thevariable-ratio belt-type transmission of the inventionas used tointerconnect the engine and-driven wheel shaft of a pedal-equippedengine-driven cycle,.FIG. 1 illustrating the condition of thetransmission prior to startingthe engine, or with the engine idling; r II f FIG. 2 is a view similar to FIG. 1, butillustratin g the conditionof the transmission during pedal-induced starting of the engine; 4 r v"FIGS. 3 and 4are sectional views respectively taken as indicated by thearrowed lines 3-3 and 44 of FIG. I r v FIG.5 is a fragmentary sectionalview taken as indicated by the arrowedline 5-5 of FIG. 4; FIG. 6 is afragmentary elevational view taken as indicated by the arrowed line 6-6of FIG. 2;'

FIG. 7 is a view similar, to FIGS; 1 and 2, but illustrating thecondition of the transmission when the engine isrunning at substantiallyfull speed with substantially maximum torque response from the drivenshaft; and

FIG. 8 is a view taken as indicated by the arrowed 0F EXEMPLARYEMBODIMENT ,OFINVENTION I Referring initially to. FIG. 1 of thedrawings, illustrated fragmentarily therein is a pedal-equippedengine-driven bicycle l0 provided'with a variable-ratio belt-typetransmission 12 of the invention, the transmission incorporating apedal-operated engine starting means as will be described in detailhereinafter.

DESCRIPTION The bicycle includes an engine 14 which is equipped with acompression release 16 to facilitate cranking of the engine prior tostarting. The engine 14 drives a rear wheel 18 of the bicycle 10 throughthe transmission 12 of the invention and a gear train 20. Also connectedto the rear wheel 18 by a chain and sprocket drive 22 is a pedalassembly 24. As will be described in detail hereinafter, the engine 14may be started by manual power applied to the pedal assembly 24, eitherwith the bicycle 10 in motion, or with the driven wheel 18 thereofsupported above ground level by a kick stand, or the like, not shown.

Considering the transmission 12 now in more detail, it includes adriving pulley or driving pulley assembly 26 on a driving shaft 28 ofthe engine 14, which driving shaft is preferably the crankshaft of theengine. The transmission 12 also includes a driven pulley or drivenpulley assembly 30 on a driven shaft 32 which, in the particularconstruction illustrated, is a shaft carrying one of the gears of thegear train 20. The driven pulley 30 is connected to the driving pulley26 by a V-belt 34 trained around the two pulleys.

As is conventional in a transmission of this type, the driving pulley 26includes two coaxial, relatively axially movable, generallyfrustoconical driving pulley members 36 and 38 which receive the V-belt34 therebetween. More particularly, the driving pulley member 38 ismovable axially toward and away from the driving pulley member 36 toincrease and decrease the pitch diameter of the driving pulley 26.Similarly, the driven pulley 30 includes two coaxial, relatively axiallymovable, generally frustoconical driven pulley members 40 and 42, thedriven pulley member 42 being axially movable toward and away from thedriven pulley member 40 .to increase and decrease the pitch diameter ofthe driven pulley.

Carried by the engine shaft 28 between the driving pulley members 36 and38, and engageable by the inner periphery of the V-belt 34, is anoverrunning clutch or clutch means 44 which is engaged when the drivenpulley 30 drives the belt, and which is disengaged when the drivingpulley 26 drives the belt. Thus, the engine 14 may be started by meansof pedal-generated power applied to the driven shaft 32 and delivered tothe engine shaft 28 through the driven pulley 30, the belt 34, theclutch 44 and, as will be explained hereinafter, the driving pulley 26.Conversely, when the engine is running so that the clutch 44 isdisengaged, power is transmitted from the driving shaft 28 to the drivenshaft 32 through the driving pulley 26, the belt 34 and the drivenpulley 30.

Considering the driving pulley 26 in more detail, the fixed drivingpulley member 36 is clamped between an annular shoulder on the engineshaft 28 and a sleeve 46 keyed to the engine shaft. Clamped against theouter end of the sleeve 46 is a disc 48 retained by a nut 50 threaded onthe outer end of the engine shaft 28, there being a lock washer 52between the nut and the disc.

Rotatable on the sleeve 46 is an outer sleeve 54 on which the drivingpulley member 38 is axially slidable. Relative rotation between thedriving pulley member 38 and the outer sleeve 54 is prevented by a key56. The movable driving pulley member 38 is biased axially away from thefixed driving pulley member 36, to tend to open the driving pulley 26and thus reduce its pitch diameter, by a spring means 58 comprisingcircumferentially-spaced radially-inwardly-extending spring fingers 60carried by the driving pulley member 38 and bearing against the disc 48.

The overrunning clutch 44 is conventional and, as best shown in FIG. 3,utilizes the sleeve 54 as its inner race. Telescoped over the sleeve 54is an outer race 62 having circumferentially spaced ramps 64 whichcircumferentially approach the sleeve 54 in the counterclockwisedirection, as viewed in FIG. 3. The inner periphery of the V-belt 34engages the outer race 62, when the driving pulley 26 is open. When theV-belt 34 is driven in the clockwise direction, as viewed in FIG. 3, bythe driven pulley 30, rollers 66 wedge between the ramps 64 and thesleeve 54 so that the clutch 44 is engaged. Conversely, when the drivingshaft 28 provides the power, the clutch 44 is disengaged.

The movable driving pulley member 38 is provided in its outer surfacewith circumferentially spaced, circumferentially extending grooves 68 ofcircumferentially decreasing depth, as best shown in FIG. 5 of thedrawings. Communicating with the deeper ends of the circumferentialgrooves 68 are radially extending grooves 70 of radially decreasingdepth. As best shown in FIG. 4, each circumferential groove 68cooperates with the corresponding radial groove 70 to provide acomposite groove which is L-shaped and which is deepest at the angle ofthe L, the depth decreasing circumferentially of the groove 68 andradially of the groove 70 from the angle of the L. Each of L-shapedcomposite grooves contains a ball 72.

During starting of the engine 14, pedal-generated power is transmittedto the V-belt 34 by the driven pulley 30 and the gear train 20. TheV-belt 34 acts on the outer race 62 of the clutch 44 to engage theclutch, thereby angularly displacing the movable driving pulley member38. Under such conditions, as best shown in FIG. 4, circumferentiallyspaced lugs 74 on the disc 48 fixed to the engine shaft 28 engage theballs 72 and force them toward the shallower ends of the circumferentialgrooves 68. This results in closing of the driving pulley 26 on theV-belt 34 to prevent slippage, and also results in torque transmissionto the engine shaft 28 to crank the engine, this being done with thecompression release 16 activated. When the engine speed is sufficientlyhigh for starting, the compression release 16 is de-activated to enablethe engine to start.

After the engine 14 has been started, and is running at idling speed,the engine shaft 28 rotates relative to the movable driving pulleymember 38 sufficiently to permit the balls 72 to enter the deepestportions of the composite L-shaped grooves in the movable driving pulleymember. This permits the driving pulley 26 to open so that it does notengage the V-belt 34. Also, the overrunning clutch 44 is now disengaged,and merely acts as an idler permitting the engine 14 to run withouttransmitting-any power to the driven pulley 30. It will be noted thatwhen the engine 14 is running, the lugs 74 on the disc 48 engage theballs 72 to drive the movable driving pulley member 38, this conditionbeing shown in FIG. 8. If the engine speed is now increasedsubstantially above idling, centrifugal force urges the balls 72radially outwardly in the grooves 70 to close the driving pulley 26 andthus increase its pitch diameter, the pitch diameter of the drivenpulley 30 decreasing correspondingly. Thus, the drive ratio of thetransmission 12 is shifted up.

Turning now to a more detailed consideration of the driven pulley 30,the fixed driven pulley member 40 is clamped against an annular shoulder76 on the driven shaft 32 by a sleeve 78 on the driven shaft. A springassembly 80 is clamped against the outer end of the sleeve 78 by anouter sleeve 82 keyed to the driven shaft 32 and retained by a nut 84and lock washer 86. The spring assembly 80 comprises circumferentiallyspaced, radial arms 88 the outer ends of which bear againstcircumferentially spaced cams or ramps 90 on the movable driven pulleymember 42, which is rotatably mounted on the sleeve 78 by means of acentral hub 92.

With the foregoing construction, when the bicycle is being propelled bythe engine 14, an increase in the load on the driven shaft 32, due, forexample, to an upgrade, results in rotation of the movable driven pulleymember 42 relative to the fixed driven pulley member 40, as the torqueovercomes the thrust of the torquesensing spring assembly 80. As theresult, the pitch diameter of the driven pulley 30 is reduced to shiftthe drive ratio down in response to the increased load.

SUMMARY OF OPERATION The operation of the transmission 12 has largelybeen explained in the course of describing its structure. Consequently,the operation will merely be summarized briefly in this section of thespecification. 7

FIG. 1 of the drawings illustrates the condition of the transmissionprior to starting the engine, or with the engine idling. Under suchcircumstances, the driving pulley 26 is open so that it does not engagethe V- belt 34. if the engine is idling, the clutch 44 is disengaged andmerely acts as an idler for the V-belt 34, without transmitting anypower thereto.

During starting of the engine 14, the conditions shown in FIGS. 2 to 6prevail. The driven pulley 30 is closed by the spring assembly 80 andpedal-generated power delivered to the driven pulley is transmitted bythe V-belt 34 to the driving pulley 26. Movement of belt 34 causesclutch 44 to engage and drive collar 54 and hence move pulley member 38,thereby closing pulley 26. The driving pulley 26 is closed slightly togrip the V-belt 34 by the action of balls 72 in the circumferentialgrooves 68.

FIGS. '7 and 8 of the drawings illustrate conditions prevailing when theengine 14 is running at substantially full speed with substantiallymaximum torque response from the driven shaft. Under such conditions,the balls 72 have partially closed the driving pulley 26 and the torqueresponsive driven pulley 30 has opened partially in opposition to theaction of the torque sensing spring assembly 80. Y I

Although an exemplary embodiment ofthe invention has been disclosed forpurposes of illustration, it will be understood that various changes,modifications, and substitutions may be incorporatedin such embodimentwithout departing from the spirit of the inventionas delined by theclaims which follow.

I claim as my invention: t

1. In a variable-ratio belt-type transmission for transmitting powerfrom a driving shaft of an engine to a driven shaft when the engine isrunning and for transmitting power from said driven shaft to saiddriving shaft to start the engine when it is not running, thecombination of:

a. a variable-pitch-diameter driving pulley for mounting on such drivingshaft and comprising two coax ial, relatively axially movable, generallyfrustoconical driving pulley members;

b. a variable-pitch-diameter driven pulley for mounting on such drivenshaft and comprising two coaxial, relatively axially movable, generallyfrustoconical driven pulley members; I

c. a V-belt trained around said driving and driven pulleys, the drivingpulley members being normally positioned to a non-belt-engagingposition;

d. overrunning clutch means positioned in between and coupled to saiddriving pulley members and engag'eable by the inner periphery of saidbelt;

e. said clutch means being adapted to be engaged and thereby couple saiddriving pulley members to said belt when said driven pulley drives saidbelt, whereby the engine may be started by means of power applied tosuch driven shaft and delivered to such driving shaft through saiddriven pulley, said belt and said clutch means;

f. said clutch means being adapted to be'disengaged and thereby uncouplesaid driving pulley from said belt when the engine is running and saiddriving pulley drives said belt; r

g. first driving-pulley closing means operable when said clutch means isengaged and responsive to torque applied to said clutch means by saidbelt for relatively moving said driving pulley members axially towardeach other into a belt engaging position; and

h. second driving-pulley closing means operable when said clutch meansisdisengaged and responsive to centrifugal force due to rotation of saiddriving pulley for relatively moving said driving pulley members axiallytoward each other into 'a beltengaging position and to vary the pitchdiameter belt-engaging position thereof. I

2. A variable-ratio belt-type transmission as defined in claim 1 whereinsaid first driving-pulley closing means includes: i

a. circumferentially extending grooves of circumferentially decreasingdepth in one of said driving pulley members; I

b. balls in each said grooves; and 1 c. means for displacing saidballs-toward the shallower ends of said grooves. v i

3. A variable-ratio belt-type transmission according to claim 2 whereinsaid second driving-pulley closing means includes: i

a. radially extending grooves of radially-outwardlydecreasing depth inone of said driving pulley members;

b. the deeper ends of said radially extending grooves respectivelycommunicating with the deeper ends of said circumferentially extendinggrooves; and

c. means for displacing said balls into the deeper ends of saidcircumferentially extending grooves so that they may move radiallyoutwardly in said radially extending grooves underthe influence ofcentrifugal force. 1 a

4. A variable-ratio belt-type transmission as set forth in claim 1including torque responsive means for axially separatingsaid drivenpulley members to decrease the pitch diameter of said driven pulley.

5. In a variable-ratio belt-type transmission according to claim 1comprising spring means for normally urging said driving pulley membersapart.

6. In a variable-ratio belt-type transmission for transmitting powerfrom a driving shaft of an engine to a driven shaft when the engine isrunning and for transmitting power from said driven shaft to saiddriving shaft to start the engine when it is not running, thecombination of:

a. a variable-pitchdiameter driving pulley for mounting on such drivingshaft and comprising two coaxial, relatively axially movable, generallyfrusto-.

conical driving pulley members;

b. a variable-pitch-diameter driven pulley for mounting on such drivenshaft and comprising two coaxial, relatively axially movable, generallyfrustoconical driven pulley members;

c. said driving and driven pulleys being adapted to receive a V-belttrained therebetween, the driving pulley members being normallypositioned to a non-belt-engaging position;

d. overrunning clutch means positioned in between and coupled to saiddriving pulley members and engageable by the inner periphery of suchbelt;

e. said clutch means being adapted to be engaged and thereby couple saiddriving pulley members to such belt when said driven pulley drives suchbelt, whereby the engine may be started by means of power applied tosuch driven shaft and delivered to such driving shaft through saiddriven pulley, such belt and said clutch means;

f. said clutch means being adapted to be disengaged and thereby uncouplesaid driving pulley from such belt when the engine is running and saiddriving pulley drives such belt;

g. first driving-pulley closing means operable when said clutch means isengaged and responsive to torque applied to said clutch means by suchbelt for relatively moving said driving pulley members axially towardeach other into a belt-engaging position; and

h. second driving-pulley closing means operable when said clutch meansis disengaged and responsive to centrifugal force caused by rotation ofsaid driving pulley for relatively moving said driving pulley membersaxially toward each other into a belt-engaging position and to vary thepitch diameter belt-engaging position thereof.

7. A variable-ratio belt-type transmission as defined in claim 6 whereinsaid first driving-pulley closing means includes:

a. circumferentially extending grooves of circumferentially decreasingdepth in one of said driving pulley members;

b. balls in each said grooves; and

c. means for displacing said balls toward the shallower ends of saidgrooves.

8. A variable-ratio belt-type transmission according to claim 7 whereinsaid second driving-pulley closing means includes:

a. radially extending grooves or radially-outwardlydecreasing depth inone of said driving pulley members; t

b. the deeper ends of said radially extending grooves respectivelycommunicating with the deeper ends of said circumferentially extendinggrooves; and

c. means for displacing said balls into the deeper ends of saidcircumferentially extending grooves so that they may move radiallyoutwardly in said radially extending grooves under the influence ofcentrifugal force.

9. In a variable-ratio belt-type transmission according to claim 6comprising spring means for normally urging said driving pulley membersapart.

10. A variable-pitch-diameter driving pulley for mounting on a drivingshaft and comprising:

a. two coaxial, relatively axially movable, generally frusto-conicaldriving pulley members;

b. the driving pulley members being normally positioned to anon-belt-engaging position and adapted to receive a V-belttherebetweeen;

c. overrunning clutch means positioned in between and coupled to saiddriving pulley members and engageable by the inner periphery of suchbelt;

d. said clutch means being adapted to be engaged and thereby couple suchbelt to said driving pulley members when driven by such belt, wherebythe engine may be started by means of power applied to such belt andsaid clutch means;

e. said clutch means being adapted to be disengaged and thereby uncouplesuch belt from said driving pulley when said driving pulley drives suchbelt;

f. first driving-pulley closing means operable when said clutch means isengaged and responsive to torque applied to said clutch means by suchbelt for relatively moving said driving pulley members axially towardeach other into a belt-engaging position; and

g. second driving-pulley closing means operable when said clutch meansis disengaged and responsive to centrifugal force caused by rotation ofsaid driving pulley for relatively moving said driving pulley membersaxially toward each other into a belt-engaging position and to vary thepitch diameter belt-engaging position thereof.

11. A variable-ratio belt-type transmission as defined in claim 10wherein said first driving-pulley closing means includes:

a. circumferentially extending grooves of circumfer entially decreasingdepthin one of said driving pulley members;

b. balls in each said grooves; and

c. means for displacing said balls toward the shallower ends of saidgrooves.

12. A variable-ratio belt-type transmission according to claim 11wherein said second driving-pulley closing means includes:

a. radially extending grooves of radially-outwardlydecreasing depth inone of said driving pulley members;

b. the deeper ends of said radially extending grooves respectivelycommunicating with the deeper ends of said circumferentially extendinggrooves; and

c. means for displacing said balls into the deeper ends of saidcircumferentially extending grooves so that they may move radiallyoutwardly in said radially extending grooves under the influence ofcentrifugal force.

13. In a variable-ratio belt-type transmission according to claim 10comprising spring means for normally urging said driving pulley membersapart.

Q UNITED STATES PATENT OFFICE @ERTWCATE OF CORRECTWN Patent bb, 3, DatedSept.

Inventofls) Bert N. Svenson It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

C01. 7, liue 52 balls" should read --a ball; line 58, "or" should read--of-- Col. 8, line 44 "balls" should read --a ball.

Signed and sealed this 19th day of February 1974.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. Attesting Officer MARSHALL DANN Commissioner ofPatents

1. In a variable-ratio belt-type transmission for transmitting powerfrom a driving shaft of an engine to a driven shaft when the engine isrunning and for transmitting power from said driven shaft to saiddriving shaft to start the engine when it is not running, thecombination of: a. a variable-pitch-diameter driving pulley for mountingon such driving shaft and comprising two coaxial, relatively axiallymovable, generally frusto-conical driving pulley members; b. avariable-pitch-diameter driven pulley for mounting on such driven shaftand comprising two coaxial, relatively axially movable, generallyfrusto-conical driven pulley members; c. a V-belt trained around saiddriving and driven pulleys, the driving pulley members being normallypositioned to a non-beltengaging position; d. overrunning clutch meanspositioned in between and coupled to said driving pulley members andengageable by the inner periphery of said belt; e. said clutch meansbeing adapted to be engaged and thereby couple said driving pulleymembers to said belt when said driven pulley drives said belt, wherebythe engine may be started by means of power applied to such driven shaftand delivered to such driving shaft through said driven pulley, saidbelt and said clutch means; f. said clutch means being adapted to bedisengaged and thereby uncouple said driving pulley from said belt whenthe engine is running and said driving pulley drives said belt; g. firstdriving-pulley closing means operable when said clutch means is engagedand responsive to torque applied to said clutch means by said belt forrelatively moving said driving pulley members axially toward each otherinto a belt engaging position; and h. second driving-pulley closingmeans operable when said clutch means is disengaged and responsive tocentrifugal force due to rotation of said driving pulley for relativelymoving said driving pulley members axially toward each other into abeltengaging position and to vary the pitch diameter belt-engagingposition thereof.
 2. A variable-ratio belt-type transmission as definedin claim 1 wherein said first driving-pulley closing means includes: a.circumferentially extending grooves of circumferentially decreasingdepth in one of said driving pulley members; b. balls in each saidgrooves; and c. means for displacing said balls toward the shallowerends of said grooves.
 3. A variable-ratio belt-type transmissionaccording to claim 2 wherein said second driving-pulleY closing meansincludes: a. radially extending grooves of radially-outwardly-decreasingdepth in one of said driving pulley members; b. the deeper ends of saidradially extending grooves respectively communicating with the deeperends of said circumferentially extending grooves; and c. means fordisplacing said balls into the deeper ends of said circumferentiallyextending grooves so that they may move radially outwardly in saidradially extending grooves under the influence of centrifugal force. 4.A variable-ratio belt-type transmission as set forth in claim 1including torque responsive means for axially separating said drivenpulley members to decrease the pitch diameter of said driven pulley. 5.In a variable-ratio belt-type transmission according to claim 1comprising spring means for normally urging said driving pulley membersapart.
 6. In a variable-ratio belt-type transmission for transmittingpower from a driving shaft of an engine to a driven shaft when theengine is running and for transmitting power from said driven shaft tosaid driving shaft to start the engine when it is not running, thecombination of: a. a variable-pitch-diameter driving pulley for mountingon such driving shaft and comprising two coaxial, relatively axiallymovable, generally frusto-conical driving pulley members; b. avariable-pitch-diameter driven pulley for mounting on such driven shaftand comprising two coaxial, relatively axially movable, generallyfrusto-conical driven pulley members; c. said driving and driven pulleysbeing adapted to receive a V-belt trained therebetween, the drivingpulley members being normally positioned to a non-belt-engagingposition; d. overrunning clutch means positioned in between and coupledto said driving pulley members and engageable by the inner periphery ofsuch belt; e. said clutch means being adapted to be engaged and therebycouple said driving pulley members to such belt when said driven pulleydrives such belt, whereby the engine may be started by means of powerapplied to such driven shaft and delivered to such driving shaft throughsaid driven pulley, such belt and said clutch means; f. said clutchmeans being adapted to be disengaged and thereby uncouple said drivingpulley from such belt when the engine is running and said driving pulleydrives such belt; g. first driving-pulley closing means operable whensaid clutch means is engaged and responsive to torque applied to saidclutch means by such belt for relatively moving said driving pulleymembers axially toward each other into a belt-engaging position; and h.second driving-pulley closing means operable when said clutch means isdisengaged and responsive to centrifugal force caused by rotation ofsaid driving pulley for relatively moving said driving pulley membersaxially toward each other into a belt-engaging position and to vary thepitch diameter belt-engaging position thereof.
 7. A variable-ratiobelt-type transmission as defined in claim 6 wherein said firstdriving-pulley closing means includes: a. circumferentially extendinggrooves of circumferentially decreasing depth in one of said drivingpulley members; b. balls in each said grooves; and c. means fordisplacing said balls toward the shallower ends of said grooves.
 8. Avariable-ratio belt-type transmission according to claim 7 wherein saidsecond driving-pulley closing means includes: a. radially extendinggrooves or radially-outwardly-decreasing depth in one of said drivingpulley members; b. the deeper ends of said radially extending groovesrespectively communicating with the deeper ends of saidcircumferentially extending grooves; and c. means for displacing saidballs into the deeper ends of said circumferentially extending groovesso that they may move radially outwardly in said radially extendinggrooves under the influence of centrifugal force.
 9. In a variable-ratiobelt-type transmission accOrding to claim 6 comprising spring means fornormally urging said driving pulley members apart.
 10. Avariable-pitch-diameter driving pulley for mounting on a driving shaftand comprising: a. two coaxial, relatively axially movable, generallyfrusto-conical driving pulley members; b. the driving pulley membersbeing normally positioned to a non-belt-engaging position and adapted toreceive a V-belt therebetweeen; c. overrunning clutch means positionedin between and coupled to said driving pulley members and engageable bythe inner periphery of such belt; d. said clutch means being adapted tobe engaged and thereby couple such belt to said driving pulley memberswhen driven by such belt, whereby the engine may be started by means ofpower applied to such belt and said clutch means; e. said clutch meansbeing adapted to be disengaged and thereby uncouple such belt from saiddriving pulley when said driving pulley drives such belt; f. firstdriving-pulley closing means operable when said clutch means is engagedand responsive to torque applied to said clutch means by such belt forrelatively moving said driving pulley members axially toward each otherinto a belt-engaging position; and g. second driving-pulley closingmeans operable when said clutch means is disengaged and responsive tocentrifugal force caused by rotation of said driving pulley forrelatively moving said driving pulley members axially toward each otherinto a belt-engaging position and to vary the pitch diameterbelt-engaging position thereof.
 11. A variable-ratio belt-typetransmission as defined in claim 10 wherein said first driving-pulleyclosing means includes: a. circumferentially extending grooves ofcircumferentially decreasing depth in one of said driving pulleymembers; b. balls in each said grooves; and c. means for displacing saidballs toward the shallower ends of said grooves.
 12. A variable-ratiobelt-type transmission according to claim 11 wherein said seconddriving-pulley closing means includes: a. radially extending grooves ofradially-outwardly-decreasing depth in one of said driving pulleymembers; b. the deeper ends of said radially extending groovesrespectively communicating with the deeper ends of saidcircumferentially extending grooves; and c. means for displacing saidballs into the deeper ends of said circumferentially extending groovesso that they may move radially outwardly in said radially extendinggrooves under the influence of centrifugal force.
 13. In avariable-ratio belt-type transmission according to claim 10 comprisingspring means for normally urging said driving pulley members apart.